Dar es Salaam vs national capital

Dar es Salaam and national capital both are nouns.

Word	Noun	Adjective	Verb	Adverb
Dar es Salaam	Yes	No	No	No
national capital	Yes	No	No	No

Dar es Salaam (noun)	national capital (noun)
the capital and largest port city of Tanzania on the Indian Ocean	the capital city of a nation